TIMEPIECE MECHANISM INDICATING INFORMATION ABOUT A SURROUNDING PRESSURE COMPRISING A RESET MECHANISM AND TIMEPIECE, SUCH AS A DIVING WATCH, COMPRISING SUCH A MECHANISM

Provided is a timepiece mechanism (1, 1′) indicating information relating to the ambient pressure. The timepiece includes an ambient pressure measuring device that deforms mechanically due to ambient pressure variation. The device includes a first wheel assembly (31) kinematically linked to the ambient pressure measuring device that rotates under the effect of an ambient pressure variation and a measured pressure indicator mechanism (40) including a measured pressure indicator organ. The device also includes a second wheel assembly (33) configured to be in uncouplable connection with the first wheel assembly (31) so thesecond wheel assembly (33) is rotated by the first wheel assembly (31) under the effect of the pressure variation. Also included is a zero-reset mechanism (100) to position the measured pressure indicator organ (44) in a reference position by uncoupling the second wheel assembly (33) from the first wheel assembly (31).